Dna construct encoding ce7-specific chimeric t cell receptor

ABSTRACT

Genetically engineered, CE7-specific redirected immune cells expressing a cell surface protein having an extracellular domain comprising a receptor which is specific for CE7, an intracellular signaling domain, and a transmembrane domain, and methods of use for such cells for cellular immunotherapy of CE7 +  neuroblastoma are disclosed. In one embodiment, the immune cell is a T cell and the cell surface protein is a single chain FvFc:  receptor where Fv designates the V H  and V L  chains of a single chain monoclonal antibody to CE7 linked by peptide, Fc represents a hinge-C H 2-C H 3 region of a human IgG 1 , and   represents the intracellular signaling domain of the zeta chain of human CD3. DNA constructs encoding a chimeric T-cell receptor and a method of making a redirected T cell expressing a chimeric T cell receptor by electroporation using naked DNA encoding the receptor are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a division of U.S. patent application Ser. No. 11/849,643 filed 4 Sep. 2007, which in turn is a division of U.S. patent application Ser. No. 11/477,572 filed 30 Jun. 2006, now U.S. Pat. No. 7,265,209, which in turn is a division of U.S. patent application Ser. No. 10/120,198 filed 11 Apr. 2002, now U.S. Pat. No. 7,070,995. Ser. No. 10/120,198 is related to claims priority under 35 U.S.C. § 119(e) to U.S. provisional patent application Ser. No. 60/282,859 filed 11 Apr. 2001. Each application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to the field of genetically engineered, redirected immune cells and to the field of cellular immunotherapy of CE7 malignancies.

The publications and other materials used herein to illuminate the background of the invention or provide additional details respecting the practice are incorporated by reference.

Neuroblastoma, a neoplasm arising from sympathetic ganglion cells, is the most common extracranial solid tumor of childhood and is third in incidence among pediatric malignancies after the leukemia-lymphoma syndromes and central nervous system tumors [1-2]. Approximately 550 new cases occur annually in the United States; seventy-nine percent of children are diagnosed prior to their fifth birthday. Stage of disease at diagnosis, patient's age at diagnosis, and characteristics of tumor cells such as histologic appearance and NMYC gene amplification are important prognostic factors which can be utilized to categorize patients into low, intermediate and high risk for poor outcome [3, 4]. While survival for low and intermediate risk neuroblastoma is excellent, the prognosis for high-risk neuroblastoma remains dismal. Despite improved tumor response rates following intensive multi-modality therapy the median response duration of high risk tumors is less than 1 year and less than 40% of patients with high risk neuroblastoma survive more than 2 years [3-6]. To date there are no treatment modalities with proven efficacy for salvaging children with recurrent/refractory disseminated neuroblastoma.

Current treatment strategies for neuroblastoma are tailored to risk-stratified algorithms based on the International Neuroblastoma Staging System (INSS) [6-9]. The primary risk factors accounted for are age at diagnosis, stage of disease, tumor histology, NMYC copy number, and DNA index. High-risk disease includes those children greater than twelve months of age with tumor dissemination (Stage IV) as well as Stage 3 and 4 disease with unfavorable histology or NMYC amplification, regardless of age [10-17]. High-risk disease accounts for more than half of newly diagnosed cases of neuroblastoma and approximately three-quarters of cases diagnosed in children greater than 12 months of age. A multi-modality maximally intensive approach to treatment of high-risk neuroblastoma has evolved that includes aggressive induction chemotherapy, surgery, radiation therapy, autologous stem cell transplantation, and post-transplant biologic therapy with cis-retinoic acid. Two successive Children's Cancer Group trials (CCG-321, CCG-3891) have demonstrated improved survival for those patients receiving myelo-ablative therapy compared to those patients receiving conventional chemotherapy [18]. Aggressive local therapy including complete surgical resection of the primary tumor and local radiation appears to decrease the incidence of primary site recurrence. Unfortunately, more than 50% of all patients and 75% of patients failing to achieve a complete remission with 1^(st) line conventional therapy continue to develop recurrent disease. Relapses typically occur in a disseminated fashion within the first 24-months after completing front-line therapy. Responses to salvage chemotherapy are limited and generally are not durable with only 8% of patients surviving greater that 3 years from time of recurrence [19-23].

Disease relapse for many children with neuroblastoma frequently occurs following the induction of a clinical complete response with standard treatment modalities, demonstrating that the persistence of minimal residual disease is a major obstacle for curative therapy. However, patients heavily treated with chemotherapy, radiation, surgery, and autologous transplantation have a limited capacity to tolerate additional cytotoxic therapeutic modalities to target minimal residual disease. The potential of targeting a limited tumor burden with immune-based approaches is attractive both, because of the opportunity to invoke immunologic effector mechanisms to which chemotherapy/radiation-resistant tumor cells are susceptible, as well as the limited toxicity theoretically possible with tumor-specific immunologic effector mechanisms.

Passive immunotherapy for neuroblastoma utilizing murine monoclonal and murine/human chimeric monoclonal antibodies have focused primarily on targeting the G_(D2) disialoganglioside present at high density on human NB [24-26]. Cheung et al. have investigated in clinical trials the G_(D2)-specific monoclonal antibody 3F8 and have reported on the safety and, more recently, the anti-tumor activity of antibody therapy in the setting of minimal residual disease [27]. The long-term outcome of patients treated with 3F8 awaits delineation, however, limitations in its use have been observed early after treatment due to the development of neutralizing HAMA responses in approximately a third of patients [27]. Additionally, failure of antibody therapy to target MRD in the CNS due to poor penetration of immunoglobulin across the blood-brain-barrier was manifested by an unusually high incidence of isolated CNS relapses in antibody treated patients.

The cloning and production of recombinant cytokines have facilitated their introduction into clinical trials designed to activate and expand immunologic effector cells in vivo. Various cytokines either alone or in combination have been evaluated in preclinical neuroblastoma animal models [28-30]. Interleukin-2 administration following transplantation has been most extensively studied as a strategy to activate NK cells and induce LAK cells. IL-2 therapy for patients with recurrent metastatic neuroblastoma failed to provide anti-tumor activity in 15 children treated [31, 32]. These studies to date have revealed a significant incidence of severe toxicities associated with high-dose IL-2 administration without a clear impact on decreasing disease relapse. The prolonged use of low-dose IL-2, although not having demonstrable anti-neuroblastoma activity, can be administered to heavily pre-treated children without severe toxicity [33]. Pession et al. have reported on the administration of 212 courses of low dose IL-2 to 17 children with neuroblastoma following stem cell transplantation [33]. These maintenance courses were delivered bimonthly over five days/course at IL-2 doses of 2×10⁶ U/m²/day escalating to 4×10⁶ U/m²/day. No life-threatening toxicities were encountered. Fever controlled by acetaminophen and transient rash were the most common side effects of therapy. Consequently, current Phase I studies are evaluating the combination of cytokines that activate effector cells operative in antibody dependent cellular cytotoxicity (IL-2 and GM-CSF) in combination with anti-G_(D2) antibody therapy [34, 35]. Frost et al. have investigated the use of monoclonal anti-GD2 antibody, 14.G2a plus IL-2 in 31 children with refractory neuroblastoma. Dose limiting toxicities included generalized pain and fever without documented infection. Tumor progression was noted in 63% of patients. Of note, 30% of patients with evaluable bone marrow disease had a significant decrease in quantity of tumor cells detected by immunohistochemical analysis [35]. The engineering of antibody-cytokine fusion molecules appears to potentiate the anti-tumor activity of either molecule administered separately in animal models, these fusion proteins are currently under investigation in clinical trials [36, 37].

Induction or augmentation of a cellular immune response against neuroblastoma is an attractive strategy for eliminating resistant tumor cells. The availability of recombinant interleukin-2 (IL-2) and the demonstration that lymphocytes cultured in high concentrations of lymphokines acquire the ability to lyse, in a non-MHC-restricted fashion, a variety of tumor types, led to trials attempting to target neuroblastoma with the adoptive transfer of autologous ex-vivo expanded LAK cells [38]. Up to 10¹¹ LAK cells have been administered in a single intravenous infusion to cancer patients without dose-limiting side effects, demonstrating the safety of adoptive therapy with large numbers of in vitro activated autologous lymphocytes. The toxicity that has been observed in these trials was attributed solely to the systemic effects of high-dose IL-2 that is required to support LAK cells in vivo [39]. LAK cell therapy in children with neuroblastoma has met with significant toxicities without obvious clinical benefit [31].

Animal models as well as a small but growing number of human tumor systems have demonstrated that anti-tumor cellular immune responses can be invoked or amplified by vaccination with tumor cells genetically modified to have enhanced immunogenicity. Transgenes that are being evaluated for neuroblastoma tumor cell vaccines include allogeneic HLA class II molecules, the co-stimulatory ligand B7-1, and pro-inflammatory cytokines [40-46]. Recently Bowman et al. published their results of a pilot study in which ten children with relapsed advanced stage neuroblastoma were treated with autologous tumor cells genetically modified to secrete IL-2 [47]. Of note, five patients had objective systemic anti-tumor responses correlating with the development of in vitro detected anti-tumor cellular cytotoxicity. These studies provide a glimpse at the potential of cellular immunotherapy for neuroblastoma but underscore the variability of inducing clinically relevant anti-tumor responses with vaccines and the technical difficulties in generating autologous genetically manipulated tumor cell lines for this application.

Antigen-specific T cells are immunologic effector cells that confer protection from lethal tumor challenge in animal models [48]. Adoptive transfer of tumor-specific T cell clones into tumor bearing hosts can eradicate established disseminated tumors. Enomoto et al. have demonstrated in a murine model system employing a poorly immunogenic syngeneic neuroblastoma, the capacity of adoptively transferred tumor-reactive cytotoxic T lymphocytes (CTL) to eradicate disseminated neuroblastoma [49]. This provocative model system, in light of the responses seen clinically to IL-2 producing tumor vaccine administration, suggest that adoptive therapy with neuroblastoma-specific T cells may have significant clinical utility provided these T cells can be reliably isolated from this patient population.

An ideal cell-surface epitope for targeting with antigen-specific T cells would be expressed solely on tumor cells in a homogeneous fashion and on all tumors within a population of patients with the same diagnosis. Modulation and/or shedding of the target molecule from the tumor cell membrane may also impact on the utility of a particular target epitope for re-directed T cell recognition. To date few “ideal” tumor-specific epitopes have been defined and secondary epitopes have been targeted based on either lack of expression on critical normal tissues or relative over-expression on tumors. Anti-G_(D2) antibodies have been most extensively utilized in antigen-specific immunotherapy for neuroblastoma. G_(D2), however, is expressed on peripheral nerves as well as brain grey matter. T cells, unlike antibody, can extensively access the CNS blood-brain barrier making G_(D2) re-directed adoptive T cell therapy subject to potentially severe neurologic toxicities [50].

Several groups have generated murine monoclonal antibodies reactive with human neuroblastoma by immunization of mice with human NB tumor cell lines. Blaser et al. have published on the generation of the CE7 monoclonal antibody (γI/κ) raised by immunizing mice with the IMR-32 human neuroblastoma cell line. CE7 uniformly binds to human neuroblastoma cell lines and primary tumors [51-53]. This high affinity IgGI monoclonal antibody (K_(a)10⁻¹¹) precipitates a 190-kDA plasma membrane-associated glycoprotein [54]. Tumor cells express in excess of 40,000 binding epitopes for CE7 and the target molecule does not shed from the cell surface. Biodistribution studies in nude mice revealed that up to 32% of injected dose/g tissue of iodinated antibody accumulates in tumor explants with low blood and organ uptake [55, 56]. Importantly, this antibody in immunohistochemistry screening of normal tissues failed to bind to all non-neuroectodermal tissues as well as brain [51]. Very weak binding was observed on adrenal medulla and sympathetic ganglia [50]. Carrel et al. have generated a mouse/human chimeric antibody and are pursuing preclinical studies for development of CE7-targeted radioimmunotherapy for neuroblastoma [56]. As with many monoclonal antibodies raised against tumor cell lines, the molecular identity of the target epitope of CE7 awaits delineation.

The safety of adoptively transferring antigen-specific CTL clones in humans was originally examined in bone marrow transplant patients who received donor-derived CMV-specific T cells [57, 80]. Studies from the laboratories of Drs. Greenberg and Riddell at the Fred Hutchinson Cancer Research Center (FHCRC) have demonstrated that the reconstitution of endogenous CMV-specific T cell responses following allogeneic bone marrow transplantation (BMT) correlates with protection from the development of severe CMV disease [58]. In an effort to reconstitute deficient CMV immunity following BMT, CD8⁺ CMV-specific CTL clones were generated from CMV seropositive HLA-matched sibling donors, expanded, and infused into sibling BMT recipients at risk for developing CMV disease. Fourteen patients were treated with four weekly escalating doses of these CMV-specific CTL clones to a maximum cell dose of 10⁹ cells/m² without any attendant toxicity [59]. Peripheral blood samples obtained from recipients of adoptively transferred T cell clones were evaluated for in vivo persistence of transferred cells. The recoverable CMV-specific CTL activity increased after each successive infusion of CTL clones, and persisted at least 12 weeks after the last infusion. However, long term persistence of CD8⁺ clones without a concurrent CD4⁺ helper response was not observed. No patients developed CMV viremia or disease. These results demonstrate that ex-vivo expanded CMV-specific CTL clones can be safely transferred to BMT recipients and can persist in vivo as functional effector cells that may provide protection from the development of CMV disease.

A complication of bone marrow transplantation, particularly when marrow is depleted of T cells, is the development of EBV-associated lymphoproliferative disease [60]. This rapidly progressive proliferation of EBV-transformed B-cells mimics immunoblastic lymphoma and is a consequence of deficient EBV-specific T cell immunity in individuals harboring latent virus or immunologically naïve individuals receiving a virus inoculum with their marrow graft. Clinical trials conducted at St. Jude's Hospital by Rooney et al. have demonstrated that adoptively transferred ex-vivo expanded donor-derived EBV-specific T cell lines can protect patients at high risk for development of this complication as well as mediate the eradication of clinically evident EBV-transformed B cells [61]. No significant toxicities were observed in the forty-one children treated with cell doses in the range of 4×10⁷ to 1.2×10⁸ cells/m².

Genetic modification of T cells used in clinical trials has been utilized to mark cells for in vivo tracking and to endow T cells with novel functional properties. Retroviral vectors have been used most extensively for this purpose due to their relatively high transduction efficiency and low in vitro toxicity to T cells [62]. These vectors, however, are time consuming and expensive to prepare as clinical grade material and must be meticulously screened for the absence of replication competent viral mutants [63]. Rooney et al. transduced EBV-reactive T cell lines with the NeoR gene to facilitate assessment of cell persistence in vivo by PCR specific for this marker gene [64]. Riddell et al. have conducted a Phase I trial to augment HIV-specific immunity in HIV seropositive individuals by adoptive transfer using HIV-specific CD8⁺ CTL clones [65]. These clones were transduced with the retroviral vector tgLS⁺HyTK which directs the synthesis of a bifunctional fusion protein incorporating hygromycin phosphotransferase and herpes virus thymidine kinase (HSV-TK) permitting in vitro selection with hygromycin and potential in vivo ablation of transferred cells with gancyclovir. Six HIV infected patients were treated with a series of four escalating cell dose infusions without toxicities, with a maximum cell dose of 5×10⁹ cells/m^(2 [)65].

As an alternate to viral gene therapy vectors, Nabel et al. used plasmid DNA encoding an expression cassette for an anti-HIV gene in a Phase I clinical trial. Plasmid DNA was introduced into T cells by particle bombardment with a gene gun [66]. Genetically modified T cells were expanded and infused back into HIV-infected study subjects. Although this study demonstrated the feasibility of using a non-viral genetic modification strategy for primary human T cells, one limitation of this approach is the episomal propagation of the plasmid vector in T cells. Unlike chromosomally integrated transferred DNA, episomal propagation of plasmid DNA carries the risk of loss of transferred genetic material with cell replication and of repetitive random chromosomal integration events.

Chimeric antigen receptors engineered to consist of an extracellular single chain antibody (scFvFc) fused to the intracellular signaling domain of the T cell antigen receptor complex zeta chain (ζ) have the ability, when expressed in T cells, to redirect antigen recognition based on the monoclonal antibody's specificity [67]. The design of scFvFc:ζ receptors with target specificities for tumor cell-surface epitopes is a conceptually attractive strategy to generate antitumor immune effector cells for adoptive therapy as it does not rely on pre-existing anti-tumor immunity. These receptors are “universal” in that they bind antigen in a MHC independent fashion, thus, one receptor construct can be used to treat a population of patients with antigen positive tumors. Several constructs for targeting human tumors have been described in the literature including receptors with specificities for Her2/Neu, CEA, ERRB-2, CD44v6, and epitopes selectively expressed on renal cell carcinoma [68-72]. These epitopes all share the common characteristic of being cell-surface moieties accessible to scFv binding by the chimeric T cell receptor. In vitro studies have demonstrated that both CD4⁺ and CD8⁺ T cell effector functions can be triggered via these receptors. Moreover, animal models have demonstrated the capacity of adoptively transferred scFvFc:ζ expressing T cells to eradicate established tumors [73]. The function of primary human T cells expressing tumor-specific scFvFc:ζ receptors have been evaluated in vitro; these cells specifically lyse tumor targets and secrete an array of pro-inflammatory cytokines including IL-2, TNF, IFN-g, and GM-CSF [74]. Phase I pilot adoptive therapy studies are underway utilizing autologous scFvFc:ζ-expressing T cells specific for HIV gp120 in HIV infected individuals and autologous scFvFc:ζ-expressing T cells with specificity for TAG-72 expressed on a variety of adenocarcinomas including breast and colorectal adenocarcinoma.

Investigators at City of Hope have engineered a CD20-specific scFvFc:ζ receptor construct for the purpose of targeting CD20+ B-cell malignancy [75]. Preclinical laboratory studies have demonstrated the feasibility of isolating and expanding from healthy individuals and lymphoma patients CD8+ CTL clones that contain a single copy of unrearranged chromosomally integrated vector DNA and express the CD20-specific scFvFc:ζ receptor [76]. To accomplish this, purified linear plasmid DNA containing the chimeric receptor sequence under the transcriptional control of the CMV immediate/early promoter and the NeoR gene under the transcriptional control of the SV40 early promoter was introduced into activated human peripheral blood mononuclear cells by exposure of cells and DNA to a brief electrical current, a procedure called electroporation [77]. Utilizing selection, cloning, and expansion methods currently employed in FDA-approved clinical trials, gene modified CD8+ CTL clones with CD20-specific cytolytic activity have been generated from each of six healthy volunteers in 15 separate electroporation procedures [76]. These clones when co-cultured with a panel of human CD20+ lymphoma cell lines proliferate, specifically lyse target cells, and are stimulated to produce cytokines.

It is desired to develop additional redirected immune cells and, in a preferred embodiment redirected T cells for treating neuroblastoma and other malignancies expressing the CE7 recognized target epitope.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides genetically engineered immune cells (referred to herein as CE7-specific redirected immune cells) which express and bear on the cell surface membrane a CE7-specific chimeric immune receptor (referred to also as CE7R) comprising an intracellular signaling domain, a transmembrane domain (TM) and a CE7-specific extracellular domain (domain derived from the variable heavy and light chain regions of the CE7 monoclonal antibody). The present invention also provides the CE7-specific chimeric immune receptors, DNA constructs encoding the receptors, and plasmid expression vectors containing the constructs in proper orientation for expression.

In a second aspect, the present invention provides a method of treating a CE7⁺ malignancy in a mammal (i.e., those malignancies which express the CE7 recognized target epitope) which comprises administering CE7-specific redirected immune cells to the mammal in a therapeutically effective amount. In one embodiment, CD8⁺ CE7-specific redirected T cells are administered, preferably with CD4⁺ CE7-specific redirected T cells. In a second embodiment, CD4⁺ CE7-specific redirected T cells are administered to a mammal (preferably in combination with CD8⁺ cytotoxic lymphocytes which express the CE7-specific chimeric receptor).

In a third aspect, the present invention provides a method of making and expanding the CE7-specific redirected T cells which comprises transfecting T cells with an expression vector containing a DNA construct encoding the CE7-specific chimeric receptor, then stimulating the cells with CE7⁺ cells, recombinant CE7, or an antibody to the receptor to cause the cells to proliferate. In one embodiment, the redirected T cells are prepared by electroporation. In a second embodiment, the redirected T cells are prepared by using viral vectors.

In another aspect, the invention provides genetically engineered stem cells which express on their surface membrane a CE7-specific chimeric immune receptor having an intracellular signaling domain, a transmembrane domain and a CE7-specific extracellular domain.

In another aspect, the invention provides genetically engineered natural killer (NK) cells which express on their surface membrane a CE7-specific chimeric immune receptor having an intracellular signaling domain, a transmembrane domain and a CE7-specific extracellular domain.

In another aspect, the invention provides genetically engineered neutrophils which express on their surface membrane a CE7-specific chimeric immune receptor having an intracellular signaling domain, a transmembrane domain and a CE7-specific extracellular domain.

In yet another aspect, the invention provides genetically engineered macrophage which express on their surface membrane a CE7-specific chimeric immune receptor having an intracellular signaling domain, a transmembrane domain and a CE7-specific extracellular domain.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A, 1B, 1C, 1D, 1E, 1F, 1G and 1H show the double-stranded DNA sequence of the plasmid containing a CE7R chimeric immunoreceptor of the present invention and show the source of the DNA found in the plasmid. The amino acid sequences of the CE7R/HyTK are also shown. The sense strand of the double-stranded DNA sequence is set forth in SEQ ID NO:5. The sense strand of the double stranded sequence coding for the CE7R chimeric receptor is set forth in SEQ ID NO:1, and the corresponding amino acid sequence is set forth in SEQ ID NO:2. The sense strand of the double stranded sequence coding for HyTK is set forth in SEQ ID NO:3, and the corresponding amino acid sequence is set forth in SEQ ID NO:4.

FIG. 2A is a schematic representation of a CE7R/scFvFc:ζ chimeric receptor.

FIG. 2B is a schematic representation of the plasmid pMG-CE7R/HyTK; the sequence which is shown in FIG. 1 A-H.

FIG. 3 shows Western blot analyses which demonstrate the expression of the CE7R/scFvFc:ζ chimeric receptor.

FIGS. 4A and 4B show the results of Fluorescent Activated Cell Sorting which demonstrate the cell surface location of the CE7R/scFvFc:ζ chimeric receptor. Flow cytometric analysis of transfected T-cells reacted with anti-murine FAB which react with the CE7 portion of the CE7R and anti-human Fc specific antibodies which react with the IgG portion of the CE7R, confirmed the cell-surface expression of the CE7R scFvFc:ζ on T cell transfectants (FIG. 4B) as evidenced by cosegregation of the CE7R antigens with known T cell antigens (FIG. 4A).

FIG. 5 is a graphical representation which shows the production of IL-2 by Jurkat T-cells expressing the CE7R/scFvFc:ζ chimeric receptor that are co-cultured with neuroblastoma cells.

FIGS. 6A-D are graphical representations showing the anti-neuroblastoma activity of primary human CD8⁺ cytotoxic T lymphocytes expressing the CE7R/scFvFc:ζ chimeric receptor.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to genetically engineered, redirected immune cells and to their use for cellular immunotherapy of malignancies which express the CE7 recognized target epitope, including, but not limited to, neuroblastoma.

In one aspect, the present invention provides genetically engineered T cells which express and bear on the cell surface membrane a CE7-specific chimeric T-cell receptor having an intracellular signaling domain, a transmembrane domain and a CE7-specific extracellular domain. The extracellular domain comprises a CE7-specific receptor. Individual T cells of the invention may be CD4⁺/CD8⁻, CD4⁻/CD8⁺, CD4⁻/CD8⁻ or CD4⁺/CD8⁺. The T cells may be a mixed population of CD4⁺/CD8⁻ and CD4⁻/CD8⁺ cells or a population of a single clone. CD4⁺ T cells of the invention produce IL-2 when co-cultured in vitro with CE7⁺ neuroblastoma cells. CD8⁺ T cells of the invention lyse CE7⁺ human neuroblastoma target cells when co-cultured in vitro with the target cells. The invention further provides the CE7-specific chimeric T-cell receptors, DNA constructs encoding the receptors, and plasmid expression vectors containing the constructs in proper orientation for expression.

In a preferred embodiment, the CE7-specific redirected T cells express CE7-specific chimeric receptor scFvFc:

, where scFv designates the V_(H) and V_(L) chains of a single chain monoclonal antibody to CE7, Fc represents at least part of a constant region of an IgG₁, and

represents the intracellular signaling domain of the zeta chain of the human CD3 complex. The extracellular domain scFvFc and the intracellular domain ζ are linked by a transmembrane (TM) domain such as the transmembrane domain of CD4. In a specific preferred embodiment, a full length scFvFc:ζ cDNA, designated CE7R, comprises the human GM-CSF receptor alpha chain leader peptide, CE7 V_(H), Gly-Ser linker, CE7 V_(L), human IgG₁ Fc, human CD4 TM, and human cytoplasmic zeta chain. “Chimeric TCR” means a receptor which is expressed by T cells and which comprises intracellular signaling, transmembrane and extracellular domains, where the extracellular domain is capable of specifically binding in an HLA unrestricted manner an antigen which is not normally bound by a T cell receptor in that manner. Stimulation of the T cells by the antigen under proper conditions results in proliferation (expansion) of the cells and/or production of cytokines (e.g., IL-2) and/or cytolysis.

In a second aspect, the present invention provides a method of treating a CE7⁺ malignancy in a mammal which comprises administering CE7-specific redirected T cells to the mammal in a therapeutically effective amount. In one embodiment of this aspect of the invention, a therapeutically effective amount of CD8⁺ CE7-specific redirected T cells are administered to the mammal. The CD8⁺ T cells are preferably administered with CD4⁺ CE7-specific redirected T cells. In a second embodiment of this aspect of the invention, a therapeutically effective amount of CD4⁺ CE7-specific redirected T cells are administered to the mammal. The CD4⁺ T cells are preferably administered with CD8⁺ T CE7-specific redirected T cells.

In a third aspect, the present invention provides a method of making and expanding the CE7-specific redirected T cells which comprises transfecting T cells with an expression vector containing a DNA construct encoding the CE7-specific chimeric receptor, then stimulating the cells with CE7⁺ cells, recombinant CE7, or an antibody to the receptor to cause the cells to proliferate. According to this aspect of the present invention, the method preferably stably transfects and re-directs T cells using electroporation of naked DNA. Alternatively, viral vectors carrying the heterologous genes are used to introduce the genes into T cells. By using naked DNA, the time required to produce redirected T cells can be significantly reduced. “Naked DNA” means DNA encoding a chimeric T cell receptor (TCR) contained in an expression cassette which comprises the structural gene for the chimeric T cell receptor to which is attached regulatory DNA regions (promoter, enhancer, polyadenylkation site and the like) that permit expression of the gene in transfected cells. The naked DNA may further be covalently bound to plasmid DNA as a DNA delivery or expression vector. The electroporation method of this invention produces stable transfectants which express and carry on their surfaces the chimeric TCR (cTCR).

In a preferred embodiment of the transfection method of the invention, the T cells are primary human T cells, such as human peripheral blood mononuclear cells (PBMC), which have previously been considered resistant to stable transfection by electroporation of plasmid vectors. Preferred conditions include the use of DNA depleted of endotoxin and electroporation within about 3 days following mitogenic stimulation of T cells. Following transfection, the transfectants are cloned and a clone demonstrating presence of a single integrated unrearranged plasmid and expression of the chimeric receptor is expanded ex vivo. The clone selected for expansion preferably is CD8⁺ and demonstrates the capacity to specifically recognize and lyse neuroblastoma target cells which express the target epitope of CE7. The clone is expanded by stimulation with IL-2 and preferably another stimulant which is specific for the cTCR.

The invention is described herein primarily with reference to the specific scFvFc:

construct and receptor of SEQ ID NOs:1 and 2, but the invention is not limited to that specific construct and receptor. The scFv portion can be replaced by any number of different CE7 binding domains, ranging from a minimal peptide binding domain, to a structured CE7 binding domain from a phage library, to antibody like domains using different methods to hold the heavy and light chain (or peptide-binding domains of each) together. The arrangement could be multimeric such as a diabody. It is possible that the T cell receptor variant is also a multimer. Multimers are most likely caused by cross pairing of the variable portion of the light and heavy chains into what has been referred to by Winters as a diabody.

The hinge portion of the construct can have multiple alternatives from being totally deleted, to having the first cysteine maintained, to a proline rather than a serine substitution, to being truncated up to the first cysteine. The Fc portion of IgG₁ can be deleted or replaced with the Fc portion of IgG₄, although there is data to suggest that the receptor preferably extends from the membrane. Any protein which is stable and dimerizes can serve this purpose. One could use just one of the Fc domains, e.g, either the C_(H)2 or C_(H)3 domain.

Alternatives to the CD4 transmembrane domain include the transmembrane CD3 zeta domain, or a cysteine mutated CD3 zeta domain, or other transmembrane domains from other transmembrane signaling proteins such as CD16 and CD8. The CD3 zeta intracellular domain was taken for activation. Intracellular signaling portions of other members of the families of activating proteins can be used, such as FcγRTIII and FcεRI. See Gross et al. [78], Stancovski et al. [68], Moritz et al. [70], Hwu et al. [79], Weijtens et al. [74], and Hekele et al. [71], for disclosures of cTCR's using these alternative transmembrane and intracellular domains.

Additional cytoplasmic domains which are known to augment lytic activity are contemplated by the present invention. Such additional cytoplasmic domains may be selected from the group including CD28 and 4-1BB. The cytoplasmic domains may be used together on a chimeric immune receptor arranged in “molecular series” or alternatively as distinct scFvFc constructs co-expressed on a redirected immune cell.

Cellular Immunotherapy Using Redirected T Cells

The strategy of isolating and expanding antigen-specific T cells as a therapeutic intervention for human disease has been validated in clinical trials [59, 80, 81]. Initial studies have evaluated the utility of adoptive T cell therapy with CD8⁺ cytolytic T cell (CTL) clones specific for cytomegalovirus-encoded antigens as a means of reconstituting deficient viral immunity in the setting of allogeneic bone marrow transplantation and have defined the principles and methodologies for T cell isolation, cloning, expansion and re-infusion [80]. A similar approach has been taken for controlling post-transplant EBV-associated lymphoproliferative disease. EBV-specific donor-derived T cells have the capacity to protect patients at high risk for this complication as well as eradicate clinically evident disease which mimics immunoblastic B cell lymphoma [81]. These studies clearly demonstrate that adoptively transferred ex vivo expanded T cells can mediate antigen-specific effector functions with minimal toxicities and have been facilitated by targeting defined virally-encoded antigens to which T cell donors have established immunity.

The application of adoptive T cell therapy as a treatment modality for human malignancy has been limited by the paucity of molecularly-defined tumor antigens capable of eliciting a T cell response and the difficulty of isolating these T cells from the tumor-bearing host. Consequently, initial cellular immunotherapy trials utilizing autologous antitumor effector cells relied on antigen nonspecific effector cells such as lymphokine activated killer (LAK) cells which had limited efficacy and pronounced toxicities [82, 83]. In an attempt to enhance the tumor-specificity of infused effector cells, IL-2 expanded tumor-infiltrating lymphocytes (TIL) were evaluated [84]. Responses to TIL infusions were sporadic due in part to the heterogeneous population of cells expanded with unpredictable antitumor specificities. Patients with melanoma and renal cell carcinoma however occasionally manifested striking tumor regressions following TIL infusions and tumor-specific MHC-restricted T cell clones have been isolated from these patients. Recently, expression cloning technologies have been developed to identify the genes encoding tumor antigens thereby facilitating the development of recombinant DNA-based vaccine strategies to initiate or augment host antitumor immunity, as well as in vitro culture systems for generating tumor-specific T cells from cancer patients [85]. Clinical trials utilizing autologous tyrosinase-specific CTL for the treatment of melanoma are currently underway and will likely provide major insights into the efficacy of targeting tumors with antigen-specific MHC-restricted T cell clones.

Endowing T cells with a desired antigen specificity based on genetic modification with engineered receptor constructs is an attractive strategy since it bypasses the requirement for retrieving antigen-specific T cells from cancer patients and, depending on the type of antigen recognition moiety, allows for targeting tumor cell-surface epitopes not available to endogenous T cell receptors. Studies to define the signaling function of individual components of the TCR-CD3 complex revealed that chimeric molecules with intracellular domains of the CD3 complex's zeta chain coupled to extracellular domains which could be crosslinked by antibodies were capable of triggering biochemical as well as functional activation events in T cell hybridomas [86]. Recent advances in protein engineering have provided methodologies to assemble single chain molecules consisting of antibody variable regions connected by a flexible peptide linker which recapitulate the specificity of the parental antibody [87, 88]. Several groups have now reported on the capacity of chimeric single chain receptors consisting of an extracellular scFv and intracellular zeta domain to re-direct T cell specificity to tumor cells expressing the antibody's target epitope; receptor specificities have included HER2/Neu, and less well characterized epitopes on renal cell and ovarian carcinoma [68, 70, 71, 74, 78, 79]. An idiotype-specific scFv chimeric TCR has been described which recognizes the idiotype-expressing lymphoma cell's surface immunoglobulin as its ligand [78]. Although this approach swaps a low affinity MHC-restricted TRC complex for a high affinity MHC-unrestricted molecular linked to an isolated member of the CD3 complex, these receptors do activate T cell effector functions in primary human T cells without apparent induction of subsequent anergy or apoptosis [74]. Murine model systems utilizing scFv:ζ transfected CTL demonstrate that tumor elimination only occurs in vivo if both cells and IL-2 are administered, suggesting that in addition to activation of effector function, signaling through the chimeric receptor is sufficient for T cell recycling [71].

Although chimeric receptor re-directed T cell effector function has been documented in the literature for over a decade, the clinical application of this technology for cancer therapy is only now beginning to be applied. ex vivo expansion of genetically modified T cells to numbers sufficient for re-infusion is required for conducting clinical trials. Not only have sufficient cell numbers been difficult to achieve, the retention of effector function following ex vivo expansion has not been routinely documented in the literature.

Treatment of CE7⁺ Malignancies with CE7-Specific Redirected T Cells

This invention represents the targeting of a universal neuroblastoma cell-surface epitope with CE7-specific redirected T cells. Neuroblastoma cells are an excellent target for redirected T cells, as they express the CE7 target epitope antigen. CE7 target epitope is an ideal target epitope for recognition by CE7-specific redirected T cells due to the prevalence of CE7⁺ disease, the uniformity of expression by tumor cells, and the stability of the CE7 target epitope molecule on the cell surface. [0050] We have found that expansion of CE7 specific re-directed CD8⁺ CTL clones with OKT3 and IL-2 routinely results in the generation of greater than 10⁹ cells over a period of approximately six weeks, and that the clones retain their effector function following expansion, as shown by functional chromium release assay data. Our observation that the plasmid/scFvFc:ζ system can generate transfectants with disrupted plasmid sequence underscores the desirability of cloning transfectants and expanding those clones demonstrating the presence of a single unrearranged integrated plasmid, expression of the chimeric receptor, and the capacity to specifically recognize and lyse CE7⁺ neuroblastoma target cells.

Equipping T cells with a suicide gene such as the herpes virus thymidine kinase gene allows for in vivo ablation of transferred cells following adoptive transfer with pharmacologic doses of gancyclovir and is a strategy for limiting the duration or in vivo persistence of transferred cells [89].

Patients can be treated by infusing therapeutically effective doses of CD8⁺ CE7-specific redirected T cells in the range of about 10⁶ to 10¹² or more cells per square meter of body surface (cells/m²). The infusion will be repeated as often and as many times as the patient can tolerate until the desired response is achieved. The appropriate infusion dose and schedule will vary from patient to patient, but can be determined by the treating physician for a particular patient. Typically, initial doses of approximately 10⁹ cells/m² will be infused, escalating to 10¹⁰ or more cells/m². IL-2 can be co-administered to expand infused cells post-infusion. The amount of IL-2 can about 10³ to 10⁶ units per kilogram body weight. Alternatively or additionally, an scFvFc:ζ-expressing CD4⁺ T_(H1) clone can be co-transferred to optimize the survival and in vivo expansion of transferred scFvFc:ζ-expressing CD8⁺ T cells.

The dosing schedule may be based on Dr. Rosenberg's published work [72-73] or an alternate continuous infusion strategy may be employed. CE7-specific redirected T cells can be administered as a strategy to support CD8⁺ cells.

It is known that chimeric immune receptors are capable of activating target-specific lysis by phagocytes, such as neutrophils and NK cells, for example (90). Thus, the present invention also contemplates the use of chimeric T-cell receptor DNA to transfect into non-specific immune cells including neutrophils, macrophages and NK cells. Furthermore, the present invention contemplates the use of chimeric T-cell receptor DNA to transfect stem cells prior to stem cell transplantation procedures.

The practice of the present invention employs, unless otherwise indicated, conventional techniques of chemistry, molecular biology, microbiology, recombinant DNA, genetics, immunology, cell biology, cell culture and transgenic biology, which are within the skill of the art. [See, e.g., 91-108].

EXAMPLES

The present invention is further detailed in the following examples, which are offered by way of illustration and are not intended to limit the invention in any manner. Standard techniques well known in the art or the techniques specifically described below are utilized.

Example 1 Construction of a scFvFc:ζ cDNA Incorporating the CE7 V_(H) and V_(L) Sequences and Expression of the Construct in T-cells

Based on the sequences published by Amstutz et al., PCR was carried out on cDNA generated from the CE7 hybridoma and cloned V_(H) and V_(L) segments were isolated and sequenced [54]. Referring now to FIG. 2A, there is shown a schematic of the CE7R/scFvFc:ζ chimeric receptor. A full length scFvFc:ζ cDNA designated CE7R was constructed using method well known in the art by PCR splice overlap extension and consists of the human GM-CSF receptor alpha chain leader peptide, CE7 V_(H), Gly-Ser linker, CE7 V_(L), human IgG₁ Fc, human CD4 TM, and human cytoplasmic zeta chain. The amino acid sequence of the receptor is shown in SEQ ID NO:2.

Referring now to FIG. 2B, there is shown a plasmid comprising the CE7R/scFvFc:ζ chimeric receptor in an expression vector. Using methods well known in the art, the cDNA construct containing the CE7R/scFvFc:ζ chimeric receptor was ligated into the multiple cloning site of a modified pMG plasmid (Invitrogen, San Diego) to generate pMG-CE7R/HyTk. This expression vector co-expresses the HyTK cDNA encoding hygromycin phosphotransferase for in vitro drug selection and the herpes thymidine kinase that renders cells susceptible to the cytotoxic action of ganciclovir. Expression of the CE7R scFvFc:ζ and HyTK is linked by the dicistronic mRNA configuration having an internal ribosome entry site (IRES). The scFvFc:ζ cDNA is 5′ to HyTK in pMG. “SpAn” represents a synthetic polyadenylation site with a strong pause site to limit transcriptional interference. The synthetic polyA site is based on the rabbit B-globin gene using a highly conserved AATAAA sequence and a GT/T rich flanking sequence downstream from the hexanucleotide sequence (109). The pause site is derived from the C2 complement gene (1110). The symbol “bGh pAn” represents the bovine growth hormone (bGh) polyadenylation (pAn) signal and a transcriptional pause site (111). It is used to minimize interference and possible recombination events. The nucleotide sequence of this plasmid is shown in SEQ ID NO:5 and FIG. 1A-H.

The CE7-specific scFvFc:ζ receptor protein is expressed in Primary Human T cells. To determine whether the CE7-specific scFvFc:ζ construct could be expressed as an intact chimeric protein, T cells were transfected with the plasmid of Example 1 containing the CE7 Chimeric receptor. Linearized plasmid was electroporated under optimized conditions and stable transfectants selected by addition of hygromycin to cultures. Referring now to FIG. 3, there are shown the results of Western blot analyses of T-cells transfected with the CE7R/scFvFc:ζ chimeric receptor in an expression vector of the present invention. Using methods known in the art, whole cell lysates from mock transfectants (cells containing the pMG plasmid without the CE7R/scFvFc:ζ chimeric receptor), T-cells transfected with the CE7R/scFvFc:ζ chimeric receptor, and T-cells transfected with another chimeric receptor (Anti CD20 scFvFc:ζ) were examined. Western blot of whole cell lysates with an anti-zeta antibody probe shows both the endogenous zeta fragment and the expected intact 66-kDa chimeric receptor protein is expressed in cells transfected with a chimeric receptor but not in cells transfected with plasmid lacking the DNA constructs of the present invention.

Referring now to FIG. 4, there are shown the results of flow cytometric analysis of the transfected cells of the present invention. Using methods known in the art and discussed in detail in the following Examples, flow cytometric analysis of transfected T-cells reacted with anti-murine FAB which react with the CE7 portion of the CE7R and anti-human Fc specific antibodies which react with the IgG portion of the CE7R, confirmed the cell-surface expression of the CE7R scFvFc:ζ on T cell transfectants as evidenced by cosegregation of the CE7R antigens with known T cell antigens.

Example 2 Anti-Neuroblastoma Effector Functions of T Cells Expressing the CE7R Chimeric Immunoreceptor

IL-2 Production

Referring now to FIG. 5, there is a graphical representation which shows the production of IL-2 by T-cells expressing the CE7R/scFvFc:ζ chimeric receptor that are co-cultured with neuroblastoma cells. Using techniques known to those skilled in the art and discussed in detail in the following examples, the function of the CE7R chimeric immunoreceptor in T cells was first assessed by expressing this scFvFc:ζ construct in Jurkat T cells. CE7R⁺ Jurkat transfectants produced IL-2 when co-cultured with a panel of neuroblastoma cell lines. IL-2 production was antigen specific as evidenced by the observations that mock transfected Jurkat cells are not activated to produce IL-2 when exposed to the same neuroblastoma stimulators and that IL-2 production was inhibited in a dose-dependent fashion by the addition to culture of soluble CE7 mAb.

Cytotolytic Activity

Referring now to FIGS. 6 A-D, there are shown graphical representations the anti-neuroblastoma activity of CD8⁺ cells expressing the CE7R/scFvFc:ζ chimeric receptor. Primary human CD4⁺ and CD8⁺ T cell clone transfectants expressing the CE7R have been generated using techniques well known in the art and discussed further in detail in the following Examples. Like Jurkat transfectants, CD4⁺ and CD8⁺ clones secrete cytokines (IFN-γ and gm-CSF) specifically upon co-culture with human neuroblastoma cells. Moreover, CE7R⁺CD8⁺ CTL clones display high levels of cytolytic activity in standard 4-hr chromium release assays against human neuroblastoma cell lines yet do not kill primary human fibroblasts (“Fibros” in FIG. 6) or other tumor lines that are devoid of the CE7 epitope (“K562” in FIG. 6).

Example 3 Generation and Characterization of T Cell Clones for Therapeutic Use

All T cells administered are TCR a/b⁺ CD4⁻CD8⁺ scFvFc:ζ⁺ T cell clones containing unrearranged chromosomally integrated plasmid DNA. T cells are isolated from the peripheral blood of patient's with recurrent/refractory neuroblastoma. Materials and methods employed to isolate, genetically modify, and expand CD8⁺ T cell clones from healthy marrow donors are detailed in Examples 4-8. T cell clones genetically modified to express the CE7R scFvFc:ζ chimeric immunoreceptor and HyTK are selected for:

-   -   a. TCRa/b⁺, CD4⁻, CD8⁺ surface phenotype as determined by flow         cytometry.     -   b. Presence of a single copy of chromosomally integrated plasmid         vector DNA as evidenced by Southern blot.     -   c. Expression of the scFvFc:ζ gene product as detected by         Western blot.     -   d. Specific lysis of human CE7⁺ cell lines in 4-hr chromium         release assays.     -   e. Dependence on exogenous IL-2 for in vitro growth.     -   f. Mycoplasma, fungal, bacterial sterility and endotoxin levels         <5 EU/ml.     -   g. In vitro sensitivity of clones to ganciclovir.

Example 4 Materials for Isolating, Genetically Modifying and Expanding CD8⁺ T Cell Clones from Healthy Marrow Donors for Therapeutic Use

1. Culture Media and Media Supplements

Culture media used in the studies include RPMI 1640 HEPES (Irvine Scientific, Irvine, Calif.) for all cell cultures. All media is purchased in 0.5 liter bottles and meets current FDA guidelines for use in adoptive immunotherapy studies in humans. Supplements to the culture media include L-glutamine (BioWhittaker, Walkersville, Md.) and fetal calf serum (Hyclone, Logan, Utah) heat inactivated at 56° C. for 30 minutes. All reagents are shipped to CRB-3008, inspected, and stored at −20° C. or 4° C. as appropriate for the reagent.

2. OKT3

Orthoclone OKT3 (Ortho) 1 mg/ml is aliquoted into sterile cryovials are stored at −20° C. in CRB-3008 until thawed for study subject T cell expansion.

3. Interleukin 2

Pharmaceutical grade recombinant human Interleukin-2 (rhIL-2) (Proleukin, Chiron, Emeryville, Calif.) is supplied in vials containing 0.67 mg of lyophilized IL-2 and having a specific activity of 1.5×10⁶ IU/mg protein. The lyophilized recombinant IL-2 is reconstituted with sterile water for infusion and diluted to a concentration of 5×10⁴ units/ml. IL-2 is aliquoted into sterile vials and stored at −20° C. in CRB-3008. rhIL-2 for direct patient administration is dispensed per standard practice.

4. Plasmid DNA

The plasmid pMG-CE7R/HyTK containing the CE7-specific scFvFc:ζ cDNA and HyTK cDNA constructs is manufactured under GLP conditions Ampules containing 100 mg of sterile plasmid DNA in 40 ml of pharmaceutical water. Vector DNA is stored in a −70° C. freezer in CRB-3008.

5. Hygromicin

The mammalian antibiotic hygromycin is used to select genetically modified T cells expressing the HyTK gene. Commercially available hygromycin (Invitrogen, San Diego, Calif.) is prepared as a sterile solution of 100 mg/ml active drug and is stored at 4° C. in CRB-3008.

6. EBV-Induced B Cell Lines

Lymphoblastoid cell lines (LCL) are necessary feeder cells for T cell expansion and have been used for this purpose in FDA-approved clinical adoptive therapy trials. An EBV-induced B cell line designated TM-LCL was established from a healthy donor by co-culture of PBMC with supernatants of the B95-8 cell line (American Type Culture Collections) in the presence of cyclosporin A. This cell line is used as an irradiated feeder cell line. This cell line has tested negative for adventitious microorganisms as well as EBV production by cord blood transformation assay. Working stocks of TM-LCL have been cryopreserved in CRB-3008 after transfer. These stocks have been thawed and retested for bacterial, fungal and mycoplasma sterility. TM-LCL feeder cells are irradiated to 8,000 cGy prior to co-culture with T cells.

7. Feeder PBMCs

Allogeneic PBMC isolated from healthy donors meeting Blood Bank criteria and laboratory screening for clinical cell product donation are harvested by leukapheresis and supplied to CRB 3008 in a collection bag following irradiation to 3,300 cGy. This apheresis product is then cryopreserved in ampules containing 50×10⁶ mononuclear cells in the CRB-3008 liquid nitrogen tank.

Example 5 Generation of CD8⁺ CTL Clones Genetically Modified to Express the CE7-Specific scFvFc:ζ Receptor (CE7R) and HyTK

1. Peripheral Blood Lymphocytes—Collection and Separation

Peripheral blood mononuclear cells (PBMC) are obtained from the study subject's designated marrow donor by leukapheresis. The mononuclear cells are separated from heparinized whole blood by centrifugation over clinical grade Ficoll (Pharmacia, Uppsula, Sweden). PBMC are washed twice in sterile phosphate buffered saline (Irvine Scientific) and suspended in culture media consisting of RPMI, 10% heat inactivated FCS, and 4 mM L-glutamine.

2. Activation of PBMC

T cells present in patient PBMC are polyclonally activated by addition to culture of Orthoclone OKT3 (30 ng/ml). Cell cultures are then incubated in vented T75 tissue culture flasks in the study subject's designated incubator. Twenty-four hours after initiation of culture rhIL-2 is added at 25 U/ml.

3. Genetic Modification of Activated PBMC

Three days after the initiation of culture PBMC are harvested, centrifuged, and resuspended in hypotonic electroporation buffer (Eppendorf) at 20×10⁶ cells/ml. 25 mg of plasmid DNA together with 400 ml of cell suspension are added to a sterile 0.2 cm electroporation cuvette. Each cuvette is subjected to a single electrical pulse of 250V/40 ms delivered by the Multiporator (Eppendorf) then incubated for ten minutes at room temperature. Following the RT incubation, cells are harvested from cuvettes, pooled, and resuspended in phenol red-free culture media containing 25 U/ml rhIL-2. Flasks are placed in the patient's designated tissue culture incubator. Three days following electroporation hygromycin is added to cells at a final concentration of 0.2 mg/ml. Electroporated PBMC are cultured for a total of 14 days with media and IL-2 supplementation every 48-hours.

4. Cloning of Hygromycin-Resistant T Cells

The cloning of hygromycin-resistant CD8⁺ CTL from electroporated OKT3-activated patient PBMC is initiated on day 14 of culture. Cells expressing FvFc product are positively selected for using antibodies to Fab and Fc and/or Protein A-FITC label using techniques well known in the art. Following incubation of electroporated cells with Fab and Fc antibody or Protein A-FITZ, cells expressing the FvFc are isolated by immunogenetic beads or columns or fluorescent activated cel sorting procedures. Viable patient PBMC are added to a mixture of 100×10⁶ cryopreserved irradiated feeder PBMC and 20×10⁶ irradiated TM-LCL in a volume of 200 ml of culture media containing 30 ng/ml OKT3 and 50 U/ml rhIL-2. This mastermix is plated into ten 96-well cloning plates with each well receiving 0.2 ml. Plates are wrapped in aluminum foil to decrease evaporative loss and placed in the patient's designated tissue culture incubator. On day 19 of culture each well receives hygromycin for a final concentration of 0.2 mg/ml. Wells are inspected for cellular outgrowth by visualization on an inverted microscope at Day 30 and positive wells are marked for restimulation.

5. Expansion of Hygromycin-Resistant Clones with CE7 Re-Directed Cytotoxicity

The contents of each cloning well with cell growth and cytolytic activity by screening chromium release assay are individually transferred to T25 flasks containing 50×10⁶ irradiated PBMC, 10×10⁶ irradiated LCL, and 30 ng/ml OKT3 in 25 mls of tissue culture media. On days 1, 3, 5, 7, 9, 11, and 13 after restimulation flasks receive 50 U/ml rhIL-2 and 15 mls of fresh media. On day 5 of the stimulation cycle flasks are also supplemented with hygromycin 0.2 mg/ml. Fourteen days after seeding cells are harvested, counted, and restimulated in T75 flasks containing 150×10⁶ irradiated PBMC, 30×10⁶ irradiated TM-LCL and 30 ng/ml OKT3 in 50 mls of tissue culture media. Flasks receive additions to culture of rhIL-2 and hygromycin as outlined above.

6. Characterization of Hygromycin-Resistant CTL Clones

a. Cell Surface Phenotype

CTL selected for expansion for use in therapy are analyzed by immunofluorescence on a FACSCalibur housed in CRB-3006 using FITC-conjugated monoclonal antibodies WT/31 (αβTCR), Leu 2a (CD8), and OKT4 (CD4) to confirm the requisite phenotype of clones (abTCR⁺, CD4⁻, and CD8⁺). Criteria for selection of clones for clinical use include uniform TCR ab⁺, CD4⁻, CD8⁺ as compared to isotype control FITC-conjugated antibody.

b. Chromosomal Integration of Plasmid

A single site of plasmid vector chromosomal integration was confirmed by Southern blot analysis. DNA from genetically modified T cell clones was screened with a DNA probe specific for the plasmid vector. The HyTK-specific DNA probe was the 420 basepair MscI/NaeI restriction fragment isolated from pMG-CE7R/HyTK. Probe DNA was ³²P labeled using a random primer labeling kit (Boehringer Mannheim, Indianapolis, Ind.). T cell genomic DNA was isolated per standard technique. Ten micrograms of genomic DNA from T cell clones was digested overnight at 37° C. with 40 units of XbaI and HindIII and then electrophoretically separated on a 0.85% agarose gel. DNA was then transferred to nylon filters (BioRad, Hercules, Calif.) using an alkaline capillary transfer method. Filters were hybridized overnight with the HyTK-specific ³²P-labeled probe in 0.5 M Na₂PO₄, pH 7.2, 7% SDS, containing 10 μg/ml salmon sperm DNA (Sigma) at 65° C. Filters were then washed four times in 40 mM Na₂PO₄, pH 7.2, 1% SDS at 65° C. and then visualized using a phosphoimager (Molecular Dynamics, Sunnyvale, Calif.). Criteria for clone selection is a single unique band with the HyTK probe.

c. Expression of the CE7-Specific scFvFc:ζ Receptor

Expression of the CE7R scFvFc:ζ receptor is determined by Western blot procedure in which chimeric receptor protein is detected with an anti-zeta antibody. Whole cell lysates of transfected T cell clones were generated by lysis of 2×10⁷ washed cells in 1 ml of RIPA buffer (PBS, 1% NP40, 0.5% sodium deoxycholate, 0.1% SDS) containing 1 tablet/10 ml Complete Protease Inhibitor Cocktail (Boehringer Mannheim). After an eighty minute incubation on ice, aliquots of centrifuged whole cell lysate supernatant were harvested and boiled in an equal volume of loading buffer under reducing conditions then subjected to SDS-PAGE electrophoresis on a precast 12% acrylamide gel (BioRad). Following transfer to nitrocellulose, membranes were blocked in blotto solution containing 0.07 gm/ml non-fat dried milk for 2 hours. Membranes were washed in T-TBS (0.05% Tween 20 in Tris buffered saline pH 8.0) then incubated with primary mouse anti-human CD3ζ monoclonal antibody 8D3 (Pharmingen, San Diego, Calif.) at a concentration of 1 mg/ml for 2 hours. Following an additional four washes in T-TBS, membranes are incubated with a 1:500 dilution of goat anti-mouse IgG alkaline phosphatase-conjugated secondary antibody for 1 hour. Prior to developing, membranes were rinsed in T-TBS then developed with 30 ml of “AKP” solution (Promega, Madison, Wis.) per the manufacturer's instructions. Criteria for clone selection is the presence of a 66 kDa chimeric zeta band.

d. Cytolytic Specificity for CE7⁺ Cells and Lack of Cytolytic Activity Against Recipient Fibroblasts Activity

CD8⁺ cytotoxic T cell clones expressing the CE7R scFvFc:ζ receptor recognize and lyse human CE7⁺ target cells following interaction of the chimeric receptor with the cell surface target epitope in an HLA unrestricted fashion. The requirements for target cell CE7 expression and class IMHC independent recognition are confirmed by assaying each αβTCR⁺, CD8⁺, CD4⁻, CE7R⁺ CTL clones against a panel of MHC-mismatched human neuroblastoma cell lines (KCNR, Be-2) as well as the CE7⁻ line K562 (a CE7-negative, NK-sensitive target) and recipient fibroblasts. T cell effectors are assayed 12-14 days following stimulation with OKT3. Effectors are harvested, washed, and resuspended in assay media; 2.5×10⁵, 1.25×10⁵, 0.25×10⁵, and 0.05×10⁵ effectors are plated in triplicate at 37° C. for 4 hours with 5×10³ target cells in V-bottom microtiter plates (Costar, Cambridge, Mass.). After centrifugation and incubation, 100 mL aliquots of cell-free supernatant is harvested and counted. Percent specific cytolysis is calculated as follows:

$\frac{\left( {{{Experimental}\mspace{14mu}}^{51}{Cr}\mspace{14mu} {release}} \right) - \left( {{{control}\mspace{14mu}}^{51}{Cr}\mspace{14mu} {release}} \right)}{\left( {{{Maximum}\mspace{14mu}}^{52}{Cr}\mspace{14mu} {release}} \right) - \left( {{{control}\mspace{14mu}}^{51}{Cr}\mspace{14mu} {release}} \right)} \times 100$

Control wells contain target cells incubated in assay media. Maximum ⁵¹Cr release is determined by measuring the ⁵¹Cr content of target cells lysed with 2% SDS. Criteria for clone selection is >50% specific lysis of both neuroblastoma targets at an effector:target ratio of 25:1 and less than 10% specific lysis of K562 and fibroblasts at an E:T ratio of 5:1.

Example 6 Microbiologic Surveillance of T Cell Cultures

Aliquots of media from the T cell cultures are plated onto bacterial and fungal growth media every 14 days. Cultures with evident contamination will be immediately discarded. To detect mycoplasma contamination, aliquots are assayed every 14 days using the Gen-Probe test kit (San Diego, Calif.) and cultures with mycoplasma contamination discarded. Prior to infusion of T cell clones and following resuspension in 0.9% saline, Gram staining will be done on the cell suspension to exclude overt contamination and endotoxin levels determined by ELISA to exclude cell product re-infusion if levels are above a 5 EU/kg burden of endotoxin is present in the cell product. T cell clones will also be cryopreserved in case archival specimens are needed.

Example 7 Quality Control Criteria for Release of Clones for Re-Infusion

The criteria set forth in Table 1 must be met prior to release of T cells for re-infusion.

TABLE 1 Criteria for Release of Clones Test for: Release Criteria: Testing Method: Viability of Clinical >90% Trypan blue exclusion Preparation Cell-Surface Phenotype Uniformly TCRa/b⁺, Flow cytometric evaluation CD4⁺, CD8⁺ with isotype controls. Vector Rearrangement Single band Southern Blot with HyTK- Specific Probe scFvFc: ζ Expression 66-kD Band Western Blot with Human Zeta-Specific Primary Antibody Anti-Neuroblastoma >50% Specific Lysis at E:T 4 hr-Chromium Release Cytolytic Activity Ratio of 25:1 Against Assay KCNR and Be-2 and <25% SL against K562 and fibros at an E:T of 5:1. Sensitivity to Ganciclovir <10% Cell viability After Trypan blue-exclusion cell 14-days of co-culture in enumeration. 5 μM ganciclovir. Sterility All screening bacterial/ Bacterial/fungal by routine fungal cultures neg for >7 clinical specimen culture. days. Mycoplasma neg at Mycoplasma by Gene-Probe time of cyropreservation RIA. and within 48 hrs of each Endotoxin by ELISA. infusion. Endotoxin level Gram stain by clinical <5 E.I./kg in washed cell microbiology lab. preparation. Gram stain negative on day of re- infusion.

Example 8 Quantitative PCR for T Cell Persistence In Vivo

The duration of in vivo persistence of scFvFc:^(ζ) CD8⁺ CTL clones in the circulation is determined by quantitative PCR (Q-PCR) utilizing the recently developed TaqMan fluorogenic 5′ nuclease reaction. Q-PCR analysis is performed by the Cellular and Molecular Correlative Core on genomic DNA extracted from study subject PBMC obtained prior to and on days +1 and +7 following each T cell infusion. Following the third infusion PBMC are also sampled on day +14, +21, +51 (Day +100 following stem cell rescue). Should any study subject have detectable gene-modified T cells on day +100, arrangements are made to re-evaluate the patient monthly until the signal is undetectable. Published data from Riddell et al. has determined that adoptively transferred T cells are detected in the peripheral blood of study subjects one day following a cell dose of 5×10⁹ cells/m² at a frequency of 1-3 cells/100 PBMC, thus the doses of cells for this study will result in a readily detectable signal (77). DNA is extracted from PBMC using the Qiagen QiAmp kit. The primers used to detect the scFvFc:ζ gene are SEQ ID NO:6: 5′-TCTTCCTCTACACAGCAAGCT CACCGTGG-3′), the 5′heavy chain Fc specific primer, and SEQ ID NO:7: 5′-GAGGGTTCTTCCT TCCTTCTCGGCTTTC-3′), the 3′HuZeta primer, which amplify a 360 basepair fragment spanning the Fc-CD4-TM-zeta sequence fusion site. The TaqMan hybridization probe is SEQ ID NO:8:5′-TTCACTCTGAAGAAGATGCCTAGCC-3′ that is 5′FAM--3′TAMRA labeled. A standard curve is generated from genomic DNA isolated from a T cell clone with a single copy of integrated plasmid spiked into unmodified T cells at frequencies of 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, and 10⁻⁶. A control primer/probe set specific for the human beta-globin gene is used to generate a standard curve for cell number and permits the calculation of the frequency of genetically modified clone in a PBMC sample. The beta-globin amplimers are as follows: SEQ ID NO:9: 5′-ACACAACTGTGTTCA CTAGC-3′ (Pco3) and SEQ ID NO:10:5′-GTCTCCTTAAACCTGTCTTG-3′ (GII) and the Taqman probe is SEQ ID NO:11: 5′-ACCTGACTCCTGAGG AGAAGTCT-3′ that is HEX5′ - - - 3′TAMRA labeled. All patients will have persistence data and immune response data to the scFvFc:ζ and HyTK genes compared to determine if limited persistence can be attributed to the development of an immune response to gene-modified T cells.

Example 9 1. Staging Criteria and Patient Eligibility

a. Staging Criteria

Prior to Treatment

-   -   Immunohistopathologically confirmed recurrent/refractory         neuroblastoma from tissue biopsy/marrow sample OR radiographic         demonstration of tumor growth/recurrence at previous         pathologically documented site of tumor.     -   CT Scan of Chest Abdomen and Pelvis with and without IV         contrast.     -   MRI of Head with and without IV contrast.     -   Bone Scan and MIBG scan (if available)     -   24-hour urine for HVA/VMA     -   Serum LDH and ferritin     -   Within 14 Days Prior to First T Cell Infusion     -   CT Scan of Chest Abdomen and Pelvis with and without IV         contrast.     -   MRI of Head with and without IV contrast.     -   Bone Scan and MIBG scan (if available providing that first scan         was positive)     -   24-hour urine for HVA/VMA     -   Serum LDH and ferritin

b. Patient Eligibility

Patient Inclusion Criteria

-   -   Recurrent disseminated neuroblastoma or disseminated         neuroblastoma that is refractory to 1^(st) line therapy.     -   Male or female subjects greater than 12 months of age.     -   Availability for peripheral blood sample drawing for study tests         as outlined in Table 2.

TABLE 2 Calender of Specific Evaluations Infusion Infusion #2 #3 Day Screening Infusion Day Day Day Day Day Day Day Day Day +56/ Day Visit #1 +1 +7 +14 +15 +21 +28 +29 +35 +42 70 +100 History and X X X X X X X X X X X X X Physical/Lansky Score CBC, DIFF, PLT X X X X X X X X X X X X X Chem 18 X X X X X X X X X X X X X EBV, HIV X Serologies Head CT* X PCR for X X X X X X X X X X X X plasmid Sequence in PBMC 24 Hr Urine for X  X* X X HVA/VMA Radiographic/  X* X X BMA& BMX Disease Response Peripheral X Blood for Immune Response *Studies are completed within 14 days prior to Infusion #1

2. Treatment Design and Rules for Dose Escalation

Peripheral blood mononuclear cells are obtained from patients by leukapheresis. Patient-derived T cell clones are generated from these leukapheresis products. Each participant receives a series of three escalating cell dose T cell infusions at two week intervals beginning as soon as clones are available and after recovery from all acute self-limited side effects of salvage chemotherapy. The salvage chemotherapy, administered by the patient's primary oncologist, is individualized to account for that child's previous treatment history, organ dysfunction, and disease sensitivity. The most common regimens are be cyclophosphamide/topotecan or ifosphamide/carboplatin/etoposide combinations, both of which have been extensively studied in children with recurrent solid tumors. The first cell dose is 10⁸ cells/m², the second 10⁹ cells/m², and the third 10¹⁰ cells/m². Recipients optionally can receive subcutaneously delivered low-dose rhIL-2 for ten days beginning 24-hrs following T cell adoptive transfer. Patients are evaluated prior to and weekly after the first infusion for a period of two months after which time, patients are evaluated monthly for an additional two months. Peripheral blood is drawn at specific times during the study to assay for the in vivo persistence of the transferred CTL clones and the induction of anti-scFvFc:ζ and HyTK immune responses. In those patients with detectable tumor at the time adoptive therapy commences, anti-tumor responses are assessed by serial radiographic studies of areas of bulky disease, and/or bone marrow cytology in those subjects with marrow infiltration, and/or tumor markers (HVA, VMA).

3. Treatment Plan

a. Schedule of Administration of CE7R⁺, CD8⁺ T Cell Clones

A series of three escalating cell dose infusions (Table 3) can be administered to patients at two-week intervals. T cell infusions commence at the earliest time of their availability provided that recipients have recovered from the acute hematologic and toxic side effects of salvage chemotherapy. For those who do not meet the specified criteria (detailed below) for T cell re-infusion at the time clones are first available, T-cell clones are cryopreserved until these criteria are met. Clones are then thawed and undergo one two-week in vitro expansion cycle prior to re-infusion. The initial two cell doses are of modest numbers and consistent with cell doses used by Greenberg and Riddell [58]. Cell dose level III is higher than previously reported for T cell clones but within cell dose range of prior LAK cell studies. Low dose s.c. IL-2 is administered in a second cohort of five patients to support the in vivo persistence of transferred CTL. IL-2 injections begin 24-hrs following adoptive transfer of T cell clones and continue for ten days following the second and third T cell infusion provided no grade 3-4 toxicity is observed with the administration of the first T cell dose or is accompanied with the second T cell dose/IL-2.

TABLE 3 CE7R⁺HyTK⁺, CD8⁺ Cytotoxic T Cell Administration Schedule Protocol Cohort 1 Cohort 2 Cell Dose Day Cell Dose Cell Dose/IL-2 I 0 1 × 10⁸ cells/m² BSA 1 × 10⁸ cells/m² BSA No IL-2 II +14 1 × 10⁹ cells/m² BSA 1 × 10⁹ cells/m² BSA s.c. IL-2 5 × 10⁵ U/m² q12 hrs ×10 days III +28  1 × 10¹⁰ cells/m² BSA 1 × 10¹⁰ cells/m² BSA s.c. IL-2 5 × 10⁵ U/m² q12 hrs ×10 days

Each infusion consists of a composite of up to five T cell clones to achieve the cell dose under study.

On the day of infusion T cell clones expanded in CRB-3008 are aseptically processed per standard technique on a CS-3000 blood separation device for cell washing and concentrating. Processed cells are resuspended in 100 ml of 0.9% NaCl with 2% human serum albumin in a bag suitable for clinical re-infusion.

Patients can be admitted to a hospital, for example, for their T cell infusions and are discharged no sooner than 23 hours following their infusion provided that no toxicities are observed. Otherwise patients remain hospitalized until resolution of any infusion-related toxicity deemed to pose a significant risk to the study subject as an outpatient.

T cells are infused intravenously over 30 minutes through a central line if available, if not an age appropriate sized I.V. catheter is inserted into a peripheral vein. The I.V tubing does not have a filter to avoid trapping of cells. The infusion bag is gently mixed every 5 minutes during the infusion.

The doctor or his representative is present during the infusion and immediately available for 2 hours following the infusion. Nursing observation and care is employed throughout the patient's hospital stay.

Subjects' oxygen saturation is measured by continuous pulse-oximetry beginning pre-infusion and continuing for at least 2 hrs or until readings return to their pre-infusion baseline.

Subjects experiencing regimen-related toxicities due to their salvage chemotherapy will have their infusion schedule delayed until these toxicities have resolved. The specific toxicities warranting delay of T cell infusions include: (a) Pulmonary: Requirement for supplemental oxygen to keep saturation greater than 95% or presence of radiographic abnormalities on chest x-ray that are progressive; (b) Cardiac: New cardiac arrhythmia not controlled with medical management. Hypotension requiring pressor support; (c) Active Infection: Positive blood cultures for bacteria, fungus, or virus within 48-hours of day 0; (d) Hepatic: Serum total bilirubin, or transaminases more than 5× normal limit; (e) Renal: Serum creatinine >2.0 or if patient requires dialysis; (f) Neurologic: Seizure activity within one week preceding day 0 or clinically detectable encephalopathy or new focal neurologic deficits; (g) Hematologic: Clinically evident bleeding diathesis or hemolysis. Platelet count must be greater than 20,000 and absolute neutrophil count greater than 500. Patients may be supported with PRBC and platelet transfusions.

b. Interleukin-2 Administration

Recombinant human IL-2 (rHuIL-2, Proleukin, Chiron, Emeryville, Calif.) resuspended for s.c. injection by standard pharmacy guidelines is administered provided that (1) no grade 3-4 toxicities are encountered in persons not receiving IL-2 at cell dose levels I-III and (2) no grade 3-4 toxicities are observed with the first and second cell doses in persons receiving IL-2. The initial IL-2 course is 5×10⁵ U/m²/dose q 12 hrs for 10 days beginning no sooner than 24-hrs following T cell re-infusion #2 and lasting no longer than 48-hrs prior to the third T cell dose (Day +28). A second IL-2 course of 5×10⁵ U/m²/dose q 12 hrs for 10 days is administered no sooner than 24-hrs following the third T cell dose provided no grade 3 or higher toxicity was encountered during the first IL-2 course. If grade 3-4 toxicity is encountered during the first IL-2 course, IL-2 is not administered following the third T cell dose. Patients not receiving IL-2 who have T cell persistence data (Q-PCR) demonstrating disappearance of clones following the third T cell infusion and those subjects receiving IL-2 who have completed the prescribed T cell infusions and IL-2 who similarly have persistence data demonstrating loss of clones in the circulation may receive further courses of IL-2 at the discretion of the treating physician.

c. Management of Toxicities and Complications

The management of mild transient symptoms such as have been observed with LAK, TIL, and T cell clone infusions symptoms is as follows. (1) All patients are pre-medicated with 15 mg/kg of acetaminophen p.o. (max. 650 mg.) and diphenhydramine 1 mg/kg I.V. (max dose 50 mg). (2) Fever, chills and temperature elevations >101° F. are managed with additional tylenol as clinically indicated, 10 mg/kg ibuprofen p.o. (max 400 mg) for breakthrough fevers, and 1 mg/kg demerol I.V. for chills (max 50 mg). Additional methods such as cooling blankets are employed for fevers resistant to these measures. All subjects that develop fever or chills have a blood culture drawn. Ceftriaxone 50 mg/kg I.V. (max dose 2 gms) is administered to non-allergic patients who in the opinion of the physician in attendance appear septic; alternate antibiotic choices are used as clinically indicated. (3) Headache is managed with acetaminophen. (4) Nausea and vomiting are treated with diphenhydramine 1 mg/kg I.V. (max 50 mg). (5) Transient hypotension is initially managed by intravenous fluid administration, however, patients with persistent hypotension require transfer to the intensive care unit for definitive medical treatment. (6) Hypoxemia is managed with supplemental oxygen.

Patients receive ganciclovir if grade 3 or 4 treatment-related toxicity is observed. Parentally administered ganciclovir is dosed at 10 mg/kg/day divided every 12 hours. A 14-day course is prescribed but may be extended should symptomatic resolution not be achieved in that time interval. All patients not hospitalized at the time of presenting symptoms are hospitalized for the first 72 hours of ganciclovir therapy for monitoring purposes. If symptoms do not respond to ganciclovir within 72 hours additional immunosuppressive agents including but not limited to corticosteroids and cyclosporin are added at the discretion of the treating physician.

d. Concomitant Therapy

All standard supportive care measures for patients undergoing therapies are used at the discretion of the patient's physician. Active infections are treated according to the standard of care.

4. Toxicities Monitored and Dosage Modifications

a. Toxicities to be Monitored

Toxicity criteria is per the NCI Common Toxicity Criteria (CTC) version 2.0 for toxicity and Adverse Event Reporting. A copy of the CTC version 2.0 is downloadable from the CTEP home page (http://ctep.info.nih.gov/l). All CTC guidelines apply to toxicity assessment except serum measurements of total bilirubin, ALT and AST as many cancer patients who have recently received chemotherapy frequently have prolonged elevations in bilirubin and hepatic transaminases. For those patients with elevated baseline serum levels of bilirubin, ALT or AST a grade 1 toxicity will be an elevation from their pre-T cell infusion baseline up to 2.5× that baseline level. Grade 2 hepatic will be a >2.5-5× rise from their pre-T cell infusion baseline, a grade 3 toxicity >5-20× rise, and grade 4>20× baseline. Any toxicity reported by research participants while receiving treatment or in follow-up for which there is no specific CTC designation will be graded on the following scale: Grade 0— no toxicity; Grade 1—mild toxicity, usually transient, requiring no special treatment and generally not interfering with usual daily activities; Grade 2—moderate toxicity that may be ameliorated by simple therapeutic maneuvers, and impairs usual activities; Grade 3—severe toxicity which requires therapeutic intervention and interrupts usual activities, hospitalization may be required or may not be required; Grade 4—life-threatening toxicity which requires hospitalization.

b. Criteria for Dose Modification

If a patient develops grade 2 toxicity with dose level I, the second cell dose for that patient remains at T cell dose level I. Only if the maximal toxicity observed with the second infusion is limited to grade 2 will the third and final cell dose be advanced to 10⁹ cells/m². For those persons requiring dose modification at cell infusion #2 who experience a grade 3 or greater toxicity with the second infusion, the third infusion is cancelled. If the first grade 2 toxicity occurs with the second cell dose, the third cell dose is held at dose level II.

c. Criteria for Removal of Patient from Treatment

If any patient develops grade 3 or higher toxicity, IL-2 if being administered, is stopped. Ganciclovir treatment as outlined above is initiated at the time a grade 3 or higher toxicity is encountered in those patients not receiving IL-2. For those patients receiving IL-2, ganciclovir treatment commences within 48-hours of stopping IL-2 if the encountered toxicity has not decreased to ≦grade 2 in that time interval. Grade 3 injection site toxicity is managed by discontinuation of IL-2 without T cell ablation with ganciclovir provided that this is the only Grade 3 or greater toxicity. Any patient requiring ganciclovir for T cell ablation do not receive further cell doses but continue being monitored per protocol. At the discretion of the treating physician, corticosteroids and/or other immunosuppressive drugs are added to ganciclovir should a more rapid tempo of resolution of severe toxicities be indicated.

d. Participant Premature Discontinuation

The reasons for premature discontinuation (for example, voluntary withdrawal, toxicity, death) are recorded on the case report form. Final study evaluations are completed at the time of discontinuation. Potential reasons for premature discontinuation include: (a) the development of a life-threatening infection; (b) the judgment of the treating physician that the patient is too ill to continue; (c) patient/family noncompliance with therapy and/or clinic appointments; (d) pregnancy; (e) voluntary withdrawal; (f) significant and rapid progression of neuroblastoma requiring alternative medical, radiation or surgical intervention; and (g) grade 3 or 4 toxicity judged to be possibly or probably related to study therapy.

5. Study Parameters and Calender Table 2

To occur concurrently with the patient's evaluation for disease relapse and prior to commencing with salvage chemotherapy. The specific studies/procedures include:

-   -   Review of pathologic specimens and/or radiographic studies to         confirm diagnosis of recurrent/refractory neuroblastoma.     -   Verify inclusion/exclusion criteria by history.     -   Administer the educational proctoring to the potential research         participant (³7-yrs of age) and the parent/legal guardian,         conduct the post-educational assessment.     -   Obtain informed consent.     -   Obtain EBV and HIV serologies.     -   Conduct staging studies as outlined above.     -   Obtain serum sample for HAMA analysis if patient has received         prior murine monoclonal antibody therapy.

(b) Isolation of Peripheral Blood Mononuclear Cells For the Initiation of T Cell Cultures

Patients satisfying inclusion criteria undergo a single leukapheresis procedure prior to receiving cytoreductive chemotherapy. The leukapheresis product is transferred to initiate T cell cultures.

(c) Day −14 to −1: Pre-T Cell Infusion Restaging

Conduct restaging studies as outlined above.

(d) Day 0: Evaluation Immediately Prior to T Cell Infusion

-   -   Review of medical status and review of systems     -   Physical examination, vital signs, weight, height, body surface         area     -   List of concomitant medications and transfusions     -   Lansky performance status (see Table 4)     -   Complete blood count, differential, platelet count     -   Chem 18     -   Blood for protocol-specific studies (see Table 2)

TABLE 4 Lansky Scale % Able to carry on 100 Fully active normal activity; no special care 90 Minor restriction in physically needed strenuous play 80 Restricted in strenuous play, tires more easily, otherwise active Mild to moderate 70 Both greater restrictions of, restriction and less time spent in active play 60 Ambulatory up to 50% of time, limited active play with assistance/supervision 50 Considerable assistance required for any active play; fully able to engage in quiet play Moderate to severe 40 Able to initiate quiet activities restriction 30 Needs considerable assistance for quiet activity 20 Limited to very passive activity initiated by others (e.g. TV) 10 Completely disabled, not even passive play

(e) Days 0, +14, +28: Clinical Evaluation During and after T Cell Infusions

Prior to the Infusion:

-   -   Interval History and Physical Exam     -   Blood draw for laboratory studies (see Table 2)

During the infusion:

-   -   Vital signs at time 0, and every 15 minutes during the infusion,         continuous pulse oximetery

Following the T cell infusion:

-   -   Vital Signs hourly for 12 hours     -   Oxygen saturation will be monitored for 2 hours following T cell         infusions. Values will be recorded prior to initiating the         infusion, immediately post-infusion, and 2 hours post-infusion.         In addition, values will be recorded every 15 minutes if they         fall below 90% until the patient recovers to his/her         pre-infusion room-air baseline saturation.     -   Events will be managed by standard medical practice.

Prior to Discharge:

-   -   Interval History and Physical Exam     -   Blood draw for laboratory studies (see Table 2)

(f) Days +1, +7, +15, +21, +29, +35, +42, +56, +70, +100

-   -   Interval History and Physical Exam     -   Blood draw for CBC, diff, plt, and Chem 18     -   3 cc/kg pt wt of heparinized (preservative-free heparin 10         U/10 ml) blood sent to CRB-3002 for direct assay of peripheral         blood lymphocytes for vector DNA by PCR

(g) Days −14-0, +42, +100

-   -   CT Scan of Sites of Recurrent Disease/MRI Head/Bone/MIBG Scans:

(h) Bone Marrow Aspirate and Biopsy: Days −14-0, +56, +100

(i) Days −1, +42, +100

-   -   24-hour urine collection for HVA, VMA

(j) If a research participant is taken off treatment after receiving T cells, restaging bone marrow evaluation will be evaluated 28 days and 56 days following the last T cell dose administered.

6. Criteria for Evaluation and Endpoint Definitions

(a) Criteria for Evaluation

The phase I data obtained at each clinical assessment is outlined in Table 2. The following toxicity and adverse event determination will be made: (a) symptoms and toxicities are evaluated as described above; (b) physical exam and blood chemistry/hematology results; and (c) adverse event reporting

(b) Disease Status

At each disease assessment outlined in Table 2 the determination of measurable disease is recorded as follows: (1) bidimensional measures of palpable disease and (2) on days +42 and +100 CT scans/MRI, bone scans, bone marrow studies, and Urine VMA/HVA determinations are evaluated and responses graded per the INSS Response Criteria (Table 5).

TABLE 5 INSS Response Criteria Definition of Response to Treatment Response Primary Metastases Markers Complete Response No tumor No tumor (chest, HVA/VMA normal (CR) abdomen, liver, bone, bone marrow, nodes, etc.) Very Good Partial Reduction >90% No tumor (as above HVA/VMA Response but <100% except bone); no decreased >90% (VGPR) improved new bone lesions, all pre-existing Partial Response Reduction 50-90% No new lesions; 50- HVA/VMA (PR) 90% reduction in decreased 50-90% measurable sites; 0- 1 bone marrow samples with tumor; bone lesions same as VGPR Minor Response No new lesions; >50% reduction of any measurable lesion (MR) (primary or metastases) with <50% reduction in any other; or <25% increase in any existing lesion.# Stable disease No new lesions; <50% reduction but <25% increase in any (SD) existing lesion.# Progressive Disease Any new lesion; increase of any measurable lesion be >25%; (PD) previous negative marrow positive for tumor #Quantitative immunohistochemical assessment does not apply to marrow disease. Shrinkage in primary tumor or metastatic sites must last 4 weeks to be considered a response.

7. Reporting Adverse Events

Any sign, symptom or illness that appears to worsen during the study period regardless of the relationship to the study agent is an adverse event. All adverse events occurring during treatment, whether or not attributed to the agent, that are observed by the physician. Attributes include a description, onset and resolution date, duration, maximum severity, assessment of relationship to the treatment agent or other suspect agent(s), action taken and outcome. Toxicities are scored according to a 0-4 scale based on the criteria delineated in the Common Toxicity Criteria (CTC) Version 2.0 (see above). Association or relatedness to the treatment are graded as follows: 1=unrelated, 2=unlikely, 3=possibly, 4=probably, and 5=definitely related.

Unexpected adverse events are those which: (a) are not previously reported with adoptive T cell therapy and (b) are symptomatically and pathophysiologically related to a known toxicity but differ because of greater severity or specificity.

Appropriate clinical, diagnostic, and laboratory measures to attempt to delineate the cause of the adverse reaction in question must be performed and the results reported. All tests that reveal an abnormality considered to be related to adoptive transfer will be repeated at appropriate intervals until the course is determined or a return to normal values occurs.

8. Statistical Considerations

The type and grade of toxicities noted during therapy are summarized for each dose level. All adverse events noted by the investigator are tabulated according to the affected body system. Descriptive statistics are used to summarize the changes from baseline in clinical laboratory parameters. For those patients with measurable tumor at the time T cell therapy commences, responses are stratified per the INSS response criteria (Table 5) and summarized. Kaplan-Meier product limit methodology are used to estimate the survival. 95% confidence intervals are calculated for all described statistics.

It will be appreciated that the methods and compositions of the instant invention can be incorporated in the form of a variety of embodiments, only a few of which are disclosed herein. It will be apparent to the artisan that other embodiments exist and do not depart from the spirit of the invention. Thus, the described embodiments are illustrative and should not be construed as restrictive.

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1. A DNA construct encoding a CE7-specific chimeric T cell receptor wherein the CE7-specific chimeric T cell receptor comprises an intracellular signaling domain, a transmembrane domain and an extracellular domain, the extracellular domain comprising a CE7-specific receptor and wherein the CE7-specific chimeric T cell receptor comprises amino acids 21-631 of SEQ ID NO:2.
 2. An expression vector containing a DNA construct of claim 1 in proper orientation for expression. 